We are currently witnessing a breakthrough in the more or less developed mechanization of the brick-lining of converters, ranging from the automation of the circuit for supplying the bricks, via systems facilitating the manual work at the brick-lining platform, to robotized systems for the complete operation of brick-lining converters. Such an installation for brick-lining a converter is, for example, described in the document FR 2,638,774.
The reasons for introducing automatic and robotized systems for brick-lining converters are essentially economic and ergonomic ones. However, the use or robots to replace manual work can only be considered when it enables virtually all manual intervention to be eliminated and when the working rate is at least as fast and accurate as manual laying.
In order to increase the speed and the accuracy of the brick-lining, the document EP 0226076 B1 proposes a working robot which is installed on a platform inside the converter and the feature of which is that the function of transporting the bricks, on the one hand, and putting these in place, on the other hand, are separate. This is effected by virtue of an automatic manipulator provided at the end of the operating arm of the robot. This operating arm brings the bricks automatically, at high speed, into a working zone forming the field of action of the manipulator and situated at a predetermined distance from the bricks already laid and from the wall of the converter in order to avoid any risk of collision. The operating arm of the robot is then immobilized in this working zone, and the manipulator performs the accurate positioning, at low speed, of the bricks.
The manipulator is equipped with feelers and with displacement detectors in order to monitor and control automatically the action of the various elements permitting the exact positioning of the bricks. The measurements supplied by the positioning detectors and feelers also make it possible to recalculate, after each laying of a brick, the movement to be made by the operating arm in order to displace the next brick into the field of action of the manipulator, and/or to order the robot, using the control computer, to select a different type of brick in order to adapt the brick-lining to the curvature and to the deformations of the wall of the converter.
This manipulator can be criticized for a certain lack of adaptability and flexibility, in particular because the bricks are held between two claws of a gripping device. This requires a very accurate operation of the manipulator since any error in calculation, however small, causes a collision with the bricks already laid, or, should the gripping device open, a brick to fall onto the bricks already laid. Moreover, the absence of the possibility of the bricks or the manipulator pivoting about a radial axis is a handicap when the laying plane is not parallel to the plane of the platform, e.g. when the laying takes place in a spiral or when the platform is slightly inclined with respect to the horizontal. Another disadvantage is that the brick is laid on the underlaying brick and against the adjacent brick before being pushed into its final position towards the wall. This friction against the adjacent and underlying bricks can cause them to be displaced and, furthermore, requires higher forces, which increases the power and the size of the manipulator.